Parse interpolated variables from SQL.

If you're implementing a backend that uses non-ANSI quoting or commenting rules, you'll need to implement a method for sqlParseVariables that calls sqlParseVariablesImpl with the appropriate quote and comment specifications.

Usage

sqlCommentSpec(start, end, endRequired)

sqlQuoteSpec(start, end, escape = "", doubleEscape = TRUE)

sqlParseVariablesImpl(sql, quotes, comments)

sqlParseVariables(conn, sql, ...)

Arguments

start, end

Start and end characters for quotes and comments

endRequired

Is the ending character of a comment required?

escape

What character can be used to escape quoting characters? Defaults to "", i.e. nothing.

doubleEscape

Can quoting characters be escaped by doubling them? Defaults to TRUE.

sql

SQL to parse (a character string)

quotes

A list of QuoteSpec calls defining the quoting specification.

comments

A list of CommentSpec calls defining the commenting specification.

Examples

# Use [] for quoting and no comments
sqlParseVariablesImpl("[?a]",
  list(sqlQuoteSpec("[", "]", "\\", FALSE)),
  list()
)
#> $start
#> integer(0)
#> 
#> $end
#> integer(0)
#> 

# Standard quotes, use # for commenting
sqlParseVariablesImpl("# ?a\n?b",
  list(sqlQuoteSpec("'", "'"), sqlQuoteSpec('"', '"')),
  list(sqlCommentSpec("#", "\n", FALSE))
)
#> $start
#> [1] 6
#> 
#> $end
#> [1] 7
#>